Subjects will begin MEC in Week 2 at 0.0/5.0 mg qd (2 tablets po qd), which will be increased to 0.0/5.0 mg po bid (2 tablets po bid) during Day 8 of the trial (Week 2). Study medications will be continued until the end of Week 8. If the subject finds the study medication, mecamylamine, to be helpful, this information can be shared with the subject’s physician to enable a decision about whether mecamylamine should be continued after the study, since it is available by prescription from the subject’s physician. Both smoker and non-smoker participants would receive supportive therapy intervention for the treatment.